Lab: Glaciers and Deserts

How does the sediment in glacial till compare to the sediment being transported by the braided streams draining away from the terminus?

-Sediments in till are unsorted -Sediment in braided streams is well sorted

What factors might affect the shape of different types of dunes?

-wind direction -vegetation -sediment supply

Imagine the valley flooding following a heavy rainstorm. Determine the depth of the lake that would fill the valley if the water reached the elevation at the point labeled with the "X" on the map below. The elevation of the hardpan is 4640 ft. The bold contour line to the west of the "X" is 5200 ft. Consider that two contour lines are between the "X" and the bold contour line.

480 ft

Desertification is a land degradation problem worldwide. -Select Deserts and Desertification Risk. -Show Political Labels and Deselect Desert - Dry Regions in the legend. Which of the following regions of the world is the most threatened by desertification?

Central and Southwest Asia

Determine what direction the wind is blowing in the sketch of the dune below. Use this information to determine what direction the dune will migrate.

Wind Direction => Dune Migration =>

What kind of desert feature is marked by the arrow in this figure?

alluvial fan

What desert landform is created when several alluvial fans overlap?

bajada

Which of the following glacial features is unique to mountain glaciation?

cirque

Identify the glacial feature indicated by the arrow in this figure.

hanging valley

Select the correct statements regarding contour lines in the Wah Wah valley map below. Select all that apply.

-The elevation gradient in the northeast corner of the map is not steep. -The elevation gradient in the southeast corner of the map is steep.

Which of the following actions would logically result in a lateral moraine?

Glaciers scrape along valley walls, knocking rock loose.

How has the changing climate in western Nebraska stabilized ancient dunes such as the Sand Hills?

Grass now grows on the Sand Hills, stabilizing them.

The Sahel is a semi-arid biogeographic and climatic transition zone between the Sahara and the Sudanian savanna comprising portions of ten African countries. The region has undergone prolonged drought since the 1980s and associated land degradation. It is a region that has been particularly prone to desertification. -Select Land Cover and select Split map window. -Zoom to Sub-Saharan Africa. Most of the areas in the Sahel experiencing "very high" desertification risk occur in what land cover type?

Grasslands

Salinization is often closely related to desertification. Salts can form crusts on the soil as saline groundwater evaporates at the surface. Conversely, root zone salinization can contribute to the salinization of shallow groundwater resources. -Remove Areas at Risk of Soil Degradation. -Select Groundwater Salinization and select Split map window. -Change Projection to Van der Grinten. Based on the distribution of salinization in Australia and South America, which agricultural type is most at risk from groundwater salinization?

Livestock ranching

What is the name of the glacial feature shown in the image below?

Medial moraine

Which of the following best describes how striations are created?

Sediments frozen in glacial ice abrade the rock.

Consider the variation in length of Nisqually Glacier on Mt. Rainier, Washington depicted on figure 14.13 in your lab manual. Why has the Nisqually Glacier retreated over the past 100 years? Check all that apply.

-More snow and ice has been removed than added -The rate of ablation is higher than the rate of accumulation

Which of the following describe the stoss side of a dune?

-Side A -Windward Side -Where erosion occurs

An increase in global mean temperatures could cause which of the following effects? Check all that apply.

-Some glaciers will completely disappear. -Fewer areas on Earth will have climates that support year-round snow and ice, conditions necessary for glaciers to form. -The amount of melting will increase in many glaciers. -The number of glaciers retreating will increase.

As discussed earlier, glaciers alter the landscape through erosion and the deposition of till. Till consists of unsorted mixtures of debris that have a large range in clast size, in which some clasts are scratched or polished by glacial drag prior to deposition. Some of the landforms created by glaciers are hanging valleys, arêtes (sharp mountain ridges), troughs, cirques (large amphitheater-type formations), and tarns (lakes that form in the empty bowl of a cirque after a glacier has melted away). Look again at the image below to familiarize yourself with the features of a glacially modified landscape. The till eroded by a glacier will eventually be deposited in piles of rubble called moraines. The appearance of moraines may provide information about a glacier. A glacier with multiple terminal or recessional moraines that exist at a lower elevation than the end (or toe) of the glacier, along with lateral moraines that extend to a lower elevation than the toe, may indicate a glacier that is receding. Most glaciers are, in fact, receding due to climate change. Look again at the Gigapan image, and note the main features in this landscape. Observe what type of glacier this is given the surrounding landscape. Compare the sizes and shapes of the various glacial zones, as well as the associated landscape features. Then, review the statements below and indicate which are correct for this particular glacier. Select all that apply.

-This glacier appears to be retreating. -It is easy to find till in this image.

Desertification is often linked to soil degradation and soil degradation, in turn, often results from poor land management practices. -Reset the map. -Select Areas at Risk of Soil Degradation and Prevailing Agricultural Practices and select Split map window. -Zoom to Sub-Saharan Africa. Which of the following agriculture practices in Sub-Saharan Africa are most associated with areas of serious concern for soil degradation?

Shifting cultivation

Select the sentence that best describes the direction of surface water flow in the figure below.

Surface water flows toward the hardpan.

The Basin and Range Province is characterized by a large number of horsts and grabens. What does this indicate about the forces that affected the crust?

Tensional forces are acting on the crust.